manoj shrivastava, ashish khandewal, akansha srivastav, s...

Rice growth and soil enzyme activities in cadmium (Cd) contaminated inceptisol Manoj Shrivastava, Ashish Khandewal, Akansha Srivastav, S.D. Singh

Centre for Environment Science and Climate Resilient Agriculture,

Indian Agricultural Research Institute, Pusa Campus, New Delhi, 110012, INDIA [email protected]

mailto:[email protected]























Rice •Rice is an important staple food crop for more than 60 per cent of the world people. •RICE consumption around the world is anticipated to continue to grow steadily at around 1.1 per cent per annum to 2025 when it is expected to reach a market volume of 570 million tonnes (Mt) •China and India will remain the world’s leading rice producers and the countries with the highest levels of production in 2016 were China (148Mt) and India (110Mt), together accounting for 59 % of rice supply.
























Problem related to heavy metals in rice

•Phytotoxicity •Yield Reduction •Human Health •Environmental pollution •Export Embargo (quarantine barrier)
























Heavy Metals •Increasingly economic growth and technological development has brought about numerous environmental problems caused by residues derived from industrial processes.

•Heavy metals when applied to the soil can accumulate and persist for long periods of time.

• These elements can be phytotoxic and harmful to vital microbial processes in nutrient cycling
























Essential and non-essential elements •Plants take up essential and non-essential elements from soils.

•Certain essential elements such as iron, manganese, molybdenum, copper, zinc, and nickel are known as micronutrients because they are required by plants in minute quantity.

•These micronutrients become toxic for plants when absorbed above certain threshold values.

•Plants also absorb non-essential elements like arsenic, cadmium, chromium, mercury, and lead which have no known biological function and are even known to be toxic at low concentrations.
























Heavy metals contamination of soils •Industrial and commercial use of metals •Metal mine tailings; • Disposal of high metal wastes in improperly protected landfills; •Leaded patrol, batteries, e-waste and lead-based paints •Land application of fertilizer, animal manures, biosolids, composts, pesticides, coal combustion residues; •Atmospheric deposition
























Fate of Metals in Soil

Once metals enter the soil: i) they can be taken up by the standing crop, ii) remain in soil in soluble and insoluble forms, or iii) leach to groundwater
























Forms of Metals in Soil

Heavy metals in soils may be present in several forms with different levels of solubility (i) dissolved (in soil solution), (ii) exchangeable (in organic and inorganic components), (iii) structural components of the lattices in soils and (iv) Insolubly precipitated with other soil components
























.

Heavy metal toxicity in plants

The affinity for heavy metals will alter the activity of the protein and create imbalances and disruption that will lead to macromolecular damage.
























Cd contamination in Rice Growing Soil •Cadmium (Cd) is one of the most toxic heavy metals, polluting the general environment.

•The application of sewage sludge, wastewaters and Cd-containing fertilizers causes an increase in Cd content in agricultural soils.

•Cd is easily taken up by plants and then enters the food chain, resulting in a serious health issue for humans.

•There is increasing concern regarding the occurrence of cadmium in rice, not only in the rice-growing areas of the Far East, but also in Europe.

•Regulatory limit of Cd in rice grain is 0.2 mg kg−1 and in soil is 3 to 6 mg kg−1
























Experimental Field Experiment in contained micro-plots (3x2 m2)

Crop--- Rice (Pusa Basmati 1121)

Metals--- Cd (mg kg-1)

Replication---4

Experimental Design–Randomized Block Design (RBD)
























Some important physiochemical properties of experimental soil Parameter Value

Soil Order Inceptisol Sand (%) 45.2

Silt (%) 30.5 Clay (%) 24.3 Texture Sandy Clay loam

pH(1:2.5)(Soil: water) 8.65 Organic Carbon (g kg-1) 12.6

Nitrogen total (g kg-1) 1 .9 CaCO3 (%) 2.7

CEC (cmol (p+) kg-1) 17. 1 Available P2O5 (mg kg-1) 53.9 Available K2O (mg kg-1) 225

Total Cd (mg kg-1) 0.54 DTPA extractable Cd (mg kg-1)

0.006
























Control Cd 25

Rice growth as affected by Cd contamination
























Rice Grain Yield as affected by Cd contamination

012345678

Control Cd25

Gra

in Y

ield

(t/h

a)

Grain Yield (t/ha)
























Cd content (mg/kg) in different pat of rice plant

Cd (mg/kg)

Control Cd contaminated soil

Grain ND 0.07±0.015

Shoot ND 2.52±0.28

Root ND 20.6±3.2
























Translocation factor

Translocation factor

Soil to Root 0.94

Root to Shoot 0.12

Shoot to Grain 0.03

Soil to Grain 0.003
























Distribution (%) of Cd in different pool in Cd contaminated soil

0

10

20

30

40

50

60

Extractable (%) Carbonate (%) Fe-Mn Oxide(%)

Organic matterbound (%)

Residual (%)

% D

istr

ibut

ion
























Catalase Activity as affected by Cd contamination

0

0.5

1

1.5

2

2.5

Root Shoot Panicle

Cata

lse

(U/g

FW

)

Catalase activity (U/g FW)

Control

Cd25
























Superoxide dismutase (SOD) Activity as affected by Cd contamination

0

100

200

300

400

500

600

Root Shoot Panicle

SOD

U/g

FW

SOD Activity

Control Cd 25
























Guaiacol Peroxidase Activity as affected by Cd contamination

0

10

20

30

40

50

60

70

80

Root Shoot Panicle

Gua

iaco

l Per

oxid

ase

(U/g

FW

) Guaiacol Peroxidase Activity

Control Cd 25
























Bacterial population in rice rhizosphere as affected by cadmium

02468

101214

control Cd25

Bac

teri

al P

opul

atio

n CF

U x

10

6 /g s

oil

Bacterial Population
























Fungal population in rice rhizosphere as affected by Cadmium

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

control Cd25Fung

al p

opul

atio

n cf

u x

106 /g

soi

l

Fungal Population
























PSM population in rice rhizosphere as affected by Cadmium

00.10.20.30.40.50.60.70.80.9

control Cd25PSM

pop

ulat

ion

cfu

x 10

6 /g s

oil

PSM Population
























Actiomycetes population in rice rhizosphere as affected by Cadmium

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

control Cd25

Act

iom

ycet

es P

opul

atio

n

cf

u x

106 /g

soi

l

Actinomycetes Population
























0

10

20

30

40

50

control Cd25

% C

olon

izat

ion

Mycorrhizal colonization

Mycorrhizal colonization on rice root as affected by Cadmium
























Rhizospheric dehydrogenase activity as affected by Cd contamination

0

2

4

6

8

10

12

Control Cd 25

Deh

ydro

gena

se a

ctiv

ity

(µg

TPF/

h/g

soil)

Dehydrogenase Activity
























Rhizospheric lipase esterase activity as affected by Cd contamination

05

1015202530354045

Control Cd25

Lipa

se e

ster

ase

acti

vity

(µ

g pN

P/g

Soi

l)

Lipase Esterase Activity
























Rhizospheric fluorescein diacetate activity as affected by Cd contamination

05

101520253035

Control Cd 25

FDA

(µg

Fluo

resc

ein/

g So

il ov

er 2

h)

Fluorescein Diacetate Activity (FDA)
























Conclusions •Cadmium does not affected the grain yield of rice significantly •Cd was found to accumulate mainly in the roots followed by shoot and grains. •Cd translocation in rice grain is within the regulatory limits •Heavy metals have significant effect upon the soil and plant enzyme activities and soil microbial community. •Further studies, including sequencing of the recovered DNA fragments are needed to identify the changes in microbial community.
























Acknowledgement •DG ICAR and Secretary DARE and Director, IARI, Government of India

•Prof. Ravi Naidu, MD and CEO CRC CARE

•Organizing Committee International Cleanup Conference 2019

•Government of Australia
























Thanks a lot!





















manoj shrivastava, ashish khandewal, akansha srivastav, s...

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